
Bat Poop Fertilizer Blamed for Deadly Fungal Infections in Cannabis Growers
Doctors have reported two rare and fatal cases of histoplasmosis, a fungal disease linked to bat guano used as fertilizer for locally grown cannabis.

Researchers at the University of Rochester detailed the unusual infections in a case report published earlier this month. Both cases involved local men who developed a severe bout of histoplasmosis, likely contracted from bat guano they had used or intended to use as fertilizer for their cannabis crops. While exposure to bat guano isn’t a common risk for many people, the researchers note that it’s become a popularly advertised “superfood” for growing cannabis.
These infections aren’t contagious and can be only caught from environmental sources of the fungus. The fungus is primarily found in the central and eastern U.S., living in the soil. But Histoplasma fungi grow especially well in soil that’s been saturated with bird or bat droppings, and the fungi seem to naturally infect bats routinely, making the furry, flighted mammals an important vector of transmission.